JPH08325033A - Optical lens for infrared and infrared sensor module - Google Patents

Abstract

PURPOSE: To obtain excellent dimensional precision by thermally melting a raw material such as Ge, Si, a Ge-Si alloy, etc., injecting the molten material into a die under pressure and cooling the molten material at a low holding pressure close to the solidifying point and at a specified pressure below the solidifying point after passing the solidifying point. CONSTITUTION: A raw material such as Ge, Si and a Ge-Si alloy is heated above the m.p. and melted, and the molten material is injected into a die with the inner face of the cavity of the die formed from a high-density carbonaceous material optically polished under a specified pressure by extrusion, injection molding, etc. The metallic material is cooled in the cavity while keeping the cavity at a relatively high forming pressure. In the course of cooling, the pressure in the die is lowered and maintained at a low holding pressure, the pressure in the die is again raised below the solidifying point, and a formed article such as a high-density and high-quality optical lens for IR is obtained. The optical lens is convexed so that the IR incident face describes a circular arc with respect to an IR element to constitute a multilens with plural convex lenses integrally formed on the inner face, and an IR sensor is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention can transmit infrared rays,
Infrared sensor module for sensing infrared optical lenses and infrared rays to collect light, and perform temperature measurement, earth resource observation, meteorological observation, pollution observation, crime prevention / disaster prevention monitoring, traffic relations, heat management process monitoring measurement Regarding

[0002]

2. Description of the Related Art As an optical lens of this type, for example, there is one disclosed in Japanese Patent Publication No. 5-47053. this is,
The lens attached to the opening of the casing was made of plastic resin such as polyethylene.

Since the lens made of the organic material having the above-mentioned structure generally has no superiority in the infrared transmittance,
Although it is possible to solve this problem by using a Fresnel lens having a thin thickness, it is disadvantageous in terms of light collection rate, distortion, etc., as compared with a general concave-convex lens.
Further, since it has no heat resistance, it cannot be used in the vicinity of lighting equipment or electric heating equipment, and there is a disadvantage that the range of use is limited.

Therefore, in order to solve the above inconvenience at once, as a lens material, an alkali halide such as NaCl, germanium (Ge) or silicon (Si) has been conventionally used.
Etc. are known. Among them, Ge and Si have a wide infrared transmission region, are extremely chemically stable, have high mechanical strength,
The Ge or Si lens has the best moisture resistance and is the highest grade lens used in an infrared image processing device such as an infrared camera.

This Ge lens manufacturing method includes steps such as Ge ingot → block processing → rough rubbing → optical polishing. Here, in the case of a spherical lens, it can be processed by rotating the optical polishing machine circularly, but in the case of an aspherical lens, it can be processed by NC.
(Numerical control) There is no choice but to process one by one using the processing method. Furthermore, in a combination of lens groups having a plurality of curved surfaces, the combination performance depends on the technology of the processing machine or craftsman. Therefore, with this manufacturing method, mass production is difficult and expensive, so the image of a high-grade lens is fixed for the Ge lens.

[0006]

Further, the method of heating and melting the raw material Ge to form the Ge lens is actually
Although it is an extremely difficult technique, for example, as a Ge lens molding method, Japanese Patent Laid-Open No. 63-157754 proposes a cast molding method from a molten state to a vacuum.

However, in the cast molding method described in the above-mentioned publication, even if the vacuum control is effective for defoaming, the mold temperature can be controlled, but since this method has no mass production effect, it is of high quality. It is not a mass production molding method. Moreover, the critical defect is that the pressure inside the cavity cannot be freely controlled, and therefore there is a limit to the high density inside the molded products of various shapes. With a simple casting method, it is not possible to control the injection pressure of the melt into the cavity during molding, the holding pressure to the melt during cooling, and the solidification expansion pressure during cooling of the material itself. Cracks, bulges, and depressions occur.

On the other hand, in the material of the molding die, the Ge melt is extremely reactive and reacts with ordinary metals, and even if the reactivity is low, a small amount of metal is required to maintain a high-purity Ge melt. We must also avoid pollution. Therefore, the selection of molding die (including mold and die) materials is important. When optical polishing is performed using a general carbon mold, the general carbon material is extremely porous, and thus the surface cannot be used. Further, the metal mold coated with a diamond thin film has problems such as joining and peeling between the coating layer and the metal, and the mold is not only extremely expensive, but also the wear of the coating layer is unavoidable. A fatal defect is that the thin film coating is easily extinguished by burning in an oxygen atmosphere, and therefore the diamond thin film coating cannot be used for coating a mold for mass production.

In view of the above situation, what the present invention is to solve is to heat and melt a raw material made of Ge, Si or Ge-Si alloy by an extrusion molding method, an injection molding method or a transfer molding method, crack,
It is an object to provide an infrared optical lens that does not bulge or sink and can be adapted to mass production, and to provide an infrared sensor module with a wide detection range.

[0010]

In order to solve the above-mentioned problems, the present invention provides an optical lens capable of transmitting infrared rays with Ge,
Composed of a raw material made of Si or Ge-Si alloy material,
In addition, the raw material is melt-molded by a molding method, and the molding method includes a molding means capable of controlling the injection pressure and the holding pressure of the melt into the molding die, and Ge, Si or G.
Melting means for heating a raw material made of an e-Si alloy material to its melting point or higher and melting the raw material, and heating the molding die to the melting point or higher of the raw material, and then melting the raw material into the cavity of the molding die at a predetermined pressure. Injecting means for injecting, cooling means for intensifying the injecting pressure after injecting and cooling while maintaining a relatively high molding pressure, and in the cooling process thereof, injecting pressure is weakened near the freezing point to maintain a low holding pressure. First maintaining means,
When passing the freezing point, the pressure is reintensified to maintain a predetermined holding pressure.

It is desirable that an extrusion molding method, an injection molding method, or a transfer molding method is used as the molding means, and a melt of the raw material is injected into a molding die.

As the molding die, a molding die in which a cavity material inner surface of a mold material made of a high-density carbon material is optically polished, or
It is desirable to use a mold in which the inner surface of the cavity of a mold material in which ceramic is coated on metal is optically polished.

An infrared element for detecting infrared rays is attached to a base having electronic parts, a casing for covering the infrared element is fixed to the base, and the infrared element is provided in an opening formed in the casing. An infrared sensor module provided with an optical lens capable of transmitting infrared rays to the optical lens, wherein the optical lens is composed of a raw material made of Ge, Si or a Ge-Si alloy material, and the raw material is melted by a molding method. Forming by molding, the molding method is a molding means capable of controlling the injection pressure and the holding pressure of the melt into the mold, and a raw material made of Ge, Si or Ge-Si alloy material is heated to a temperature higher than its melting point. Melting means for melting by melting and a pouring means for heating the molding die to a temperature equal to or higher than the melting point of the raw material and then pouring the melt of the raw material into the cavity of the molding die at a predetermined pressure. Cooling means for strengthening the subsequent injection pressure and cooling while maintaining a relatively high molding pressure; first maintaining means for weakening the injection pressure near the freezing point to maintain a low holding pressure in the cooling process thereof; and freezing point And second holding means for strengthening the pressure again to maintain a predetermined holding pressure when passing through the optical lens, and the infrared incident surface of the optical lens is a curved convex surface that draws an arc with respect to the infrared detecting portion. And a multi-lens in which a plurality of convex lenses are integrally formed on the inner surface.

The casing and the optical lens are
The casing and the optical lens are integrally melt-molded by the above-mentioned molding method, and are made of a raw material made of e, Si or Ge-Si alloy material.

An engaged portion is formed on the casing, and an engaging portion for engaging with the engaged portion of the casing to fix the optical lens to the casing is formed on the optical lens. is there.

It is desirable that an extrusion molding method, an injection molding method, or a transfer molding method is used as the molding means, and the melt of the raw material is injected into the molding die.

Further, as the molding die, a molding die in which a cavity material inner surface of a mold material made of a high-density carbon material is optically polished,
Alternatively, it is desirable to use a mold in which the inner surface of the cavity of a mold material in which ceramic is coated on metal is optically polished.

[0018]

The infrared optical lens of the present invention having the above-mentioned contents is composed of a raw material made of Ge, Si or Ge-Si alloy material, and the raw material is heated to a temperature higher than its melting point to be melted and a molding die is formed. After being heated to the melting point of the raw material or higher, the melt of the raw material is injected into the cavity of the molding die at a predetermined pressure, whereby the melt is partially solidified even if the melt of the raw material is cooled by the molding die. In other words, it is uniformly injected under pressure into the cavity of the molding die.
Also, after injecting the melt of the raw material into the cavity of the mold,
By increasing the pressure for injecting the raw material into the mold and cooling it while maintaining a relatively high molding pressure, the density of the melt can be increased. And in the cooling process,
By weakening the injection pressure near the freezing point and maintaining a low holding pressure, the pressure of solidification expansion of the material is absorbed and the occurrence of internal strain is prevented. Then, when it passes the freezing point, the pressure is reintensified to maintain a predetermined holding pressure, so that the density of the molded product can be increased and high dimensional accuracy can be obtained, and the molded product can be cracked, swollen, and depressed. Does not occur. By this melt molding method, an optical lens made of Ge, Si or a Ge-Si alloy material can be manufactured in one molding step.

In this case, an extrusion molding method, an injection molding method, and a transfer molding method are used as the molding means, and the raw material melt is injected into the molding die, whereby the molding process is simplified and mass production can be achieved. Moreover, the molding pressure can be increased and a high-density molded product can be obtained.

As the molding die, a molding die in which the inner surface of the cavity of a mold material made of a high-density carbon material is optically polished, or
By using a mold in which the inner surface of the cavity of a mold material with ceramic coating on metal is optically polished, impurities are not mixed in the melt, the mold has excellent durability, and it is suitable for mass production and requires post-processing. Therefore, it is possible to manufacture an optical lens that does not have the above.

By using the above-mentioned molding means,
The optical lens can be easily configured as a multi-lens in which a plurality of convex lenses are integrally formed on the inner surface such that the infrared incident surface of the optical lens is a curved convex surface that draws an arc with respect to the infrared element. As shown in, it becomes possible to greatly enlarge the incident angle with respect to infrared rays as compared with a flat lens. Then, the incident infrared ray can be reliably focused on the light receiving portion of the infrared element by the convex lens.

Further, the casing and the optical lens are made of Ge,
Composed of a raw material made of Si or Ge-Si alloy material,
Moreover, by integrally melting and molding the casing and the optical lens by the molding method, it is not necessary to separately form the casing, and the work of assembling the optical lens and the casing is also unnecessary. Moreover, Ge, Si or G
Since the e-Si alloy material is a semiconductor material, it has a shielding effect against electromagnetic waves and can always perform accurate detection without being affected by external electrical noise and the like.

Further, by forming the engaged portion on the casing and the engaging portion on the optical lens, the engaged portion of the casing and the engaging portion of the optical lens are simply engaged.
The assembling work is completed, and the work time can be shortened as compared with the assembling by soldering or the like.

[0024]

EXAMPLE A method of manufacturing an optical lens capable of transmitting infrared rays will be described. This optical lens is composed of a raw material made of Ge, Si or a Ge-Si alloy material, and
The raw material is melt-molded by a molding method, and its specific structure will be described. FIG. 1 shows a simplified molding cycle of pressure (P) and temperature (T) according to the melt molding method, the horizontal axis represents the pressure of the mold clamping cylinder,
The vertical axis represents the temperature of the melt or the mold. This molding cycle is a means for controlling the injection pressure and the holding pressure of the melt into the molding die, and a melting means (A → B: heating) for heating and melting the Ge, Si or Ge-Si alloy material to its melting point or higher. Process), after heating the molding die above the melting point of the raw material, pouring means (B → C: pouring process) for pouring the melt of the raw material into the cavity of the molding die at a predetermined pressure. Cooling means for strengthening and cooling while maintaining a relatively high molding pressure (C → D molding / cooling process), and first maintaining means for weakening the injection pressure near the freezing point to maintain a low holding pressure in the cooling process. (D → E → F: pressure reduction / pressure retention process),
A second maintaining means (F → G → H: pressurizing / pressurizing process) that reinforces the pressure when passing the freezing point to maintain a predetermined holding pressure.
Then, after cooling to room temperature, the pressure is reduced and the molded product is taken out from the molding die (H → A: pressure reduction / mold release process), and the molding process is completed.

Here, a raw material melt made of Ge, Si or a Ge--Si alloy material (Ge: mp = 958.5 ° C., Si: m.
p. = 1414 ° C.) is similarly injected into a molding die heated above the melting point of the raw material by extrusion molding, injection molding or transfer molding to mold. The cavity of the molding die (mold) is molded according to the size and purpose of the optical lens R, the inner surface of which is optically polished, and the raw material is melted to give a freezing point (generally) in the molding die. When it is peeled off after being cooled to a temperature equal to or lower than the melting point), a high precision infrared lens molded product having a mirror-like appearance of the optical polishing level of Ge, Si or Ge-Si alloy, which is unnecessary for post-processing, is molded. .

Further, the material for the molding die needs the following selection criteria. (1) Ge and Si are high-purity semiconductor materials, and if metal contamination occurs, the performance in the infrared transmission region and the like deteriorates. Therefore, use a material that does not cause contamination or reaction as the material in contact with the melt. thing. (2) The mold should be a material that keeps the mirror surface by optical polishing. (3) A material having physical properties very similar to the characteristic properties (thermal conductivity, expansion coefficient) when solidifying Ge or Si melt. In the present invention, as a mold satisfying the above conditions, a high-density carbon mold (mold) having an inner surface optically polished or a composite mold (mold having a ceramic layer coated on a heat-resistant metal and an optical polishing treatment on the surface of the coating layer) ) Is adopted.

The most suitable molding method is an extrusion molding method, a transfer molding method or an injection molding method having a large mass production effect, which enables molding with a higher packing density than the vacuum casting method. According to these methods, the packing density of the molded product is high, and when molded into a lens, the transmittance is as excellent as that of a crystalline body. By adopting these molding means, the injection pressure of the melt, the holding pressure when the mold is cooled, the solidification expansion when the material itself is cooled, etc. are controlled. That is, after injecting the melt at a predetermined injection pressure into the forming die, the injection pressure is strengthened to maintain a relatively high forming pressure for cooling, the high forming pressure is maintained up to the freezing point of the melt, and then near the freezing point. The injection pressure is weakened to reduce the pressure, and when it passes the freezing point, the pressure is strengthened again to increase the pressure, and the holding pressure is maintained until the temperature is sufficiently lowered.

Next, FIG. 2 shows a first molding apparatus for manufacturing a Ge lens by using a transfer molding method and a high-density carbon mold as a molding die, and FIG. 3 shows a molding method using an injection molding method. A second molding apparatus for manufacturing a lens having a special Ge shape is shown by using a composite mold in which a heat-resistant metal is ceramic-coated as a mold, and these devices will be described.

The molding die 1 used in the first molding apparatus is
A mold processed with a carbon material used as a material of a high-frequency melting furnace for melting Ge is used, and a portion corresponding to the cavity is assembled with a processed product of a high-density carbon material and its inner surface is optically polished. Is. The high-density carbon material can be obtained by processing a high-performance optically polished surface which has not been obtained by the conventional porous carbon material.
Further, since the parts other than the cavity that come into contact with the Ge melt are all made of a carbon material, there is no risk of the melt being contaminated.

In the first molding apparatus, the molding die 1 is arranged in the central portion of the holding frame 2, an air cylinder 3 is arranged above the holding frame 2, and the air cylinder 3 is supplied. A plunger 4 which is displaced according to air pressure and is inserted into the molding die 1 is provided, and a compressed air supply system 5 for operating the air cylinder 3 is further provided.
The heating furnace 6 that can be controlled in the temperature range of 00 ° C. is provided. A load cell 4a is attached to the plunger 4 to measure and control the pressure. The air cylinder 3 has a first air supply port 3a for pushing the plunger 4 and a second air supply port 3b for retracting the plunger 4.
The compressed air supply system 5 supplies compressed air to the air supply ports 3a and 3b. Here, the compressed air supply system 5 branches the compressed air supplied from a compressor (not shown) into two, and respectively divides the compressed air into the first pressure reducing valve 7 and the second pressure reducing valve 7.
It is supplied to the pressure reducing valve 8, and then the first pressure reducing valve 7 to the pressure gauge 9
Is supplied to the solenoid valve 10 via the second pressure reducing valve 8 via the pressure gauge 11 into two solenoid valves 12 and 13, and is supplied to the solenoid valve 10 and the outlet side of the solenoid valve 10 and the solenoid valve 12. Is supplied to the first air supply port 3a and supplied from the electromagnetic valve 13 to the second air supply port 3b. The pressure of the air supplied to the air supply ports 3a and 3b is set by reducing the supply pressure of the compressor to a predetermined value by adjusting the pressure reducing valves 7 and 8, respectively. In this embodiment, the first pressure reducing valve 7 is set to a high pressure and the second pressure reducing valve 8 is set to a low pressure. The solenoid valves 10 and 1 are
The pipes on the outlet side of lines 2 and 13 are connected to lines 10a and 12 respectively.
a, 13a.

In order to manufacture a Ge infrared lens by the first molding apparatus, first, a granular Ge raw material powder (about 2-3
mmΦ) is a gas supply pipe 1 having a pipe formed under the molding die 1
Flow a reducing gas, such as forming gas, from 4,
The moisture in the raw material powder is replaced, the solenoid valve 13 is opened, compressed air is supplied from the line 13a to the second air supply port 3b of the air cylinder 3, and the plunger 4 is set in the upper position. The furnace 6 is operated to heat the raw material powder and the mold 1. Here, the temperature of the molding die 1 and the temperature in the heating furnace 6 are measured by a temperature monitor 15 to control the temperature. When the temperature of the molding die 1 becomes higher than the melting point of the raw material on the temperature monitor 15, the solenoid valve 10 is opened to supply compressed air of high pressure to the first air supply port 3a of the air cylinder 3 from the line 10a, The electromagnetic valve 13 is closed and the plunger 4 is moved downward to apply pressure to the molding die 1 to pressurize the melt of the raw material in the cavity and maintain it. This pressure is the molding pressure. Next, the temperature of the heating furnace 6 is lowered, the heating of the heating furnace 6 is stopped, or the mold 1 is cooled by forced air cooling or the like. This cooling rate is optimally set according to the thickness and heat capacity of the molded product. Then, when cooling is continued and the temperature drops to near the freezing point of the raw material, the solenoid valve 10 is closed and the solenoid valve 12 is opened to open the line 1
Compressed air having a low pressure is supplied from 2a to the first air supply port 3a, and the pressure applied to the mold 1 by the plunger 4 is lowered to maintain the holding pressure. After that, when the temperature of the mold 1 passes through the freezing point of the raw material and drops, the solenoid valve 12 is closed and the solenoid valve 10 is opened to supply compressed air of high pressure from the line 10a to the first air supply port 3a. The pressure applied to the mold 1 by the plunger 4 is increased to maintain the high holding pressure. In this pressure-holding process, basically, the injection pressure is increased and the holding pressure at the time of cooling is sufficiently maintained as a control condition for high-density molding.

Next, the second molding apparatus will be described with reference to FIG. The molding die 16 of this molding apparatus is made of heat-resistant metal (SK
Steel, hastelloy, etc.), and the inside that comes into contact with the raw materials is all ceramic-coated. This molding apparatus fixes one of the molds 16 to a stationary platen 18 which is vertically arranged in a housing 17 to form the mold 1.
The other mold of 6 is the mold clamping ram 20 of the mold clamping cylinder 19.
It is fixed to the movable platen 21 attached to the tip of the, and the raw material reservoir 22 and the injection cylinder 23 communicating with the raw material reservoir 22 are laterally provided in the housing 17, and the injection cylinder 23 has a piston 25 of an injection / pressure holding cylinder 25. Can be inserted by driving compressed air or the like. Further, the nozzle portion at the tip of the injection cylinder 23 penetrates the fixed platen 18 and is connected to the molding die 16. A horizontal heating furnace 26 for melting the raw material powder is arranged around the injection cylinder 23, and a heater 27 for controlling the mold temperature is arranged around the molding die 16. Furthermore,
At the upper part of the housing 17, gas supply ports 28, ... Are provided in a section accommodating the molding die 16, an inside of the raw material reservoir 22 and a section in which the horizontal heating furnace 26 is provided, respectively. Forming gas is supplied from the system 29 to each part in the housing 17. Here, the inner surface of the injection cylinder 23 in which the raw material is melted is also ceramic-coated. In addition, the first of the injection and pressure holding cylinder 24
A compressed air supply system (not shown) similar to the above is connected to the air supply port 24a and the second air supply port 24b to change the pressure and flow path of the compressed air supplied to the injection / pressure-holding cylinder 24 and to change the piston. The pressure applied to the mold 16 is adjusted by 25.

In order to manufacture a lens having a special Ge shape by the above-mentioned second molding apparatus, first, a granular Ge raw material powder is filled in the raw material reservoir 22 and a forming gas is caused to flow from above to purify the surface of the raw material. To do. Then, a pressure fluid is supplied to the mold clamping cylinder 19 to advance the mold clamping ram 20 to close the mold 16. Next, with the piston 25 retracted, the raw material is introduced into the injection cylinder 23, and then the piston 25 is advanced to move the raw material powder to the portion of the horizontal heating furnace 26 to heat and melt it. On the other hand, the molding die 16 is heated to a temperature equal to or higher than the melting point of the raw material by the heater 27 around the molding die 16 and the melt is melted.
Inject into the cavity of. A load cell 4a for monitoring pressure fluctuations is attached to the piston 25, and the heater 2 for controlling the pressure (holding pressure) required to hold the melt inside the cavity of the molding die 16 and the die temperature.
At 7, molding and cooling are controlled. Then, while the holding pressure is applied, the melt is cooled and molded, the mold clamping ram 20 is retracted, the molding die 16 is released, and the molded product is taken out.
The details of the pressure and temperature control in this case are the same as those described above, and will be omitted.

As the molding die 16, a molding die made of a high-density carbon material may be used, and molten Si may be injection-molded in the molding die to manufacture an optical lens, or a metal may be ceramic-coated. Ge-Si using a mold
Optical lenses made of alloys may be manufactured.

Optical lens R molded by the above-mentioned molding method
The infrared sensor module M of the present invention using
This infrared sensor module M shown in FIG.
Is composed of an infrared element N for detecting infrared rays, a casing K for covering the infrared element N, and an optical lens R provided in an opening formed in the casing K, and is radiated from a human body. Infrared rays generated by the infrared element N can be detected.

The infrared element N has a metal package 30 having an airtight seal and an electromagnetic shield, an optical filter 31 as an infrared transmission window provided in an opening formed in the metal package 30, and a light transmitted through the optical filter 31. It is composed of a pair of light receiving portions 32, 32 for receiving infrared rays.

The infrared element N is attached to a printed board 34 having electronic parts, and the casing K is
It is fixed to the print board 34 by soldering. Reference numeral 34a shown in the drawing is a screw hole formed in the printed board 34, and 33 is a casing for covering electronic parts and the like protruding downward from the lower end of the printed board 34. .

The pair of light receiving portions 32, 32 are connected so that the directions of polarization processing are opposite to each other, and both light receiving portions 3 are provided for infrared rays incident through the optical filter 31.
Although 2 and 32 function, they are not output to disturbances such as a temperature change around the sensor and mechanical impact that have the same phase.

As shown in FIGS. 4 and 5, the optical lens R is constructed as a multi-lens in which a plurality of convex lenses r projecting inward are integrally formed on one inner surface of the optical lens R. The infrared ray incident surface is configured to be a curved convex surface that draws a circular arc with respect to the infrared element N, and the incident angle Z with respect to infrared rays can be greatly enlarged as compared with a flat lens, and a plurality of convex lenses can be provided. Infrared rays incident by r are received by the light receiving portions 32, 3 of the infrared ray element N.
It is possible to surely focus the light to 2.

The casing K is made of the same Ge material as the optical lens R, and is integrally melt-molded with the optical lens R by the above-mentioned molding method, and the casing K itself has a shielding effect against electromagnetic waves. In addition to exhibiting, the casing K is formed separately, and the optical lens R
The work of assembling the casing K and the casing K can be eliminated.

Further, as described above, the outer surface of the optical lens R is finished into a mirror surface which is unnecessary for post-processing in the cavity of the optically polished molding die (mold), and the inner and outer surfaces of the optical lens R are Each is subjected to infrared coating treatment with a transparent thin film. Specifically, the outer surface of the lens is surface-treated with an infrared multilayer coating so that the transmission region functions as a 6-micron cut-on filter, and the inner surface of the lens is
The surface is treated with a single layer of transparent thin film so as to be non-reflective.

In addition to integrally melting and molding the casing K and the optical lens R, as shown in FIGS. 6 and 7, a separately formed metallic casing K is joined to the optical lens R by soldering or the like. Alternatively, the material of the casing K can be freely selected. In this case, there is an advantage that the inner surface coating process of the optical lens R can be easily performed as compared with the case of performing the optical lens R integrally melt-molded with the casing K.

As shown in FIGS. 8 and 9, the optical lens R is constructed so as to have the same width as the width of the optical filter 31 of the infrared element N, and the infrared sensor module M.
The size of the optical lens R can be freely set. In addition to providing a plurality of convex surfaces r on the inner surface of the optical lens R, it may be provided on a part of the inner surface of the optical lens R, a part of the outer surface, or the entire outer surface. The shape of the optical lens R can be freely set, for example, by configuring R itself as a Fresnel lens.

A concave lens manufactured by the above-described molding method is shown in FIG. 10, and the entire infrared ray incident side surface of the concave lens R is coated with a metal layer 35 formed by depositing a metal such as Al or Au. It is configured to function as a condenser mirror.

Further, in FIG. 11, a metal layer 36 formed by vapor-depositing a metal such as Al or Au is coated on the concave lens R except for the central portion of the infrared ray incident side surface thereof in the same manner as described above. Therefore, the metal layer 36 portion can collect infrared rays, and the portion 36a without the metal layer 36 can function as an interference filter that transmits infrared rays.

As another embodiment of the lens R, FIG.
2 shows. This is because an infrared element N for detecting infrared rays is attached to a base 34 having electronic parts, a metal casing K for covering the infrared element N is fixed to the base 34 by soldering, and the casing K A lens R capable of transmitting infrared rays to the infrared element N is plated and then joined to the opening formed in the above. This plating process, in other words, the Ni electroless plating process, or the plating process part 37 after the electrolytic plating process
After being washed and dried, they are joined with a low melting point metal, solder or the like. It should be noted that the numbers not described in FIG. 12 are the same as the above-mentioned same numbers, and thus the description thereof will be omitted.

Both the front and back surfaces of the lens R are coated for the purpose of suppressing reflection, and these two coating layers 38 and 39 function as an interference filter that transmits only specific wavelengths. .

As the infrared sensor module M,
In addition to thermocouples and bolometers, various detectors can be used as long as they can detect infrared rays, such as photon detectors.

A method of assembling the optical lens R and the casing K may be as shown in FIG. This is because a guide groove 40 having a substantially inverted L shape in a side view is formed in the casing K, a recess 40a as an engaged portion of the casing K is formed on the guide terminal end side of the guide groove 40, and the guide groove 40 of the casing K is formed. An engaging piece having an inverted L shape in a side view, in which an engaging convex portion 41a as an engaging portion for engaging the groove portion 40 to fix the optical lens R to the casing K is provided at the lower end of the optical lens R. 41 is formed. Therefore, after inserting the engaging piece 41 of the optical lens R into the groove 40 of the casing K from above, by rotating the optical lens R clockwise, the engaging protrusion of the engaging piece 41 is inserted into the recess 40a of the groove 40. The optical lens R is fixed to the casing K by engaging 41a. By rotating the optical lens R counterclockwise from the fixed state of the optical lens R, the engagement can be released and the optical lens R can be removed from the casing K. Also, in the figure, the engaging portion 41a
Although only one set of the engaged part 40a and the engaged part 40a is shown, two or more sets may be provided, and the number and shape of these may be freely changed.

The outer surface of the casing K is not mirror-finished as described above, but is rough and is not subjected to any coating treatment with the above-mentioned transparent thin film. Alternatively, coating treatment may be performed.

As described above, the lower end of the casing K is
By fixing to the upper surface of the printed board 34 by soldering, the shield effect at this soldered portion is not attenuated.

The raw materials for the casing K are Ge and S.
You may comprise i or Ge-Si alloy material.

The metal package 30 of the infrared element A is made of a raw material made of Ge, Si or a Ge--Si alloy material, and the optical filter 31 of the infrared element A is G.
You may comprise from the raw material which consists of e, Si, or Ge-Si alloy material. By forming the optical filter 31 in the optical lens R of the present invention, the casing K that covers the infrared element A, the optical lens R that covers the opening of the casing K, and the like can be omitted.

[0054]

The optical lens is made of Ge, Si or Ge-S.
Since it can be obtained by melt-forming a raw material made of an i alloy material by a forming method, the pressure of solidification expansion of the material can be absorbed to prevent internal strain, and the density of the formed article can be increased, High dimensional accuracy can be obtained, and cracks, swelling, and depressions do not occur in the molded product, and disadvantages in manufacturing due to variations in products can be avoided. Moreover, as in the conventional case, it is possible to effectively use the Ge, Si or Ge-Si alloy material, which has a higher material cost than the polishing processing by the optical polishing machine, without waste, and even in the vicinity of the lighting equipment or the electric heating equipment. It is possible to provide an infrared optical lens having a wide applicable range that can be used. Further, even if a lens having a short focal point is produced by the above-mentioned molding method, distortion and aberration are small, so that the lens can be downsized and the infrared transmittance can be improved. It is also possible to improve the S / N ratio and reduce malfunctions of various devices caused by external factors such as noise.

By constructing the optical lens so that its infrared ray incident surface is a curved convex surface that draws an arc with respect to the infrared ray element, the incident angle can be expanded as compared with a flat lens. , Infrared rays that can be reliably focused on the light receiving part of the infrared ray element by the convex lens integrally formed on the inner surface, and the detection range can be expanded while avoiding detection errors due to distortion etc. A sensor module can be provided.

The casing is made of Ge, Si or Ge-
Compared with the case where two members separately formed by integrally forming the optical lens by a molding method, which is made of a raw material made of a Si alloy material, in terms of an assembly work surface and a manufacturing surface. In addition to being advantageous, since the casing itself has an electromagnetic wave shielding effect, it is possible to provide a highly reliable infrared sensor module which can always perform accurate detection without special electromagnetic shielding.

If the engaged portion is formed on the casing and the engaging portion for engaging with the engaged portion of the casing to fix the optical lens to the casing is formed on the optical lens, a separate structure is formed. It is possible to provide an infrared sensor module which can be made advantageous in terms of assembly work and can be shortened in manufacturing time, as compared with the case where these two are joined by soldering or the like.

By using an extrusion molding method, an injection molding method, or a transfer molding method as the molding means, the molding process is simplified, mass production is facilitated, the density of the molded product can be increased, and It is possible to take advantage of the molding method as it is when manufacturing a large number of products or manufacturing a two-dimensional array compound lens or the like.

As the molding die, a molding die in which the cavity inner surface of a mold material made of a high-density carbon material is optically polished or a molding die in which the cavity inner surface of a metal-ceramic coated ceramic material is optically polished is used. It is possible to inexpensively manufacture a lens having an optical surface that is free from impurities, has excellent durability of a molding die, is suitable for mass production, and does not require post-processing.

[Brief description of drawings]

FIG. 1 is a graph of a molding cycle showing the relationship between the injection cylinder pressure and the material temperature in the melt molding method.

FIG. 2 is a simplified explanatory view showing a molding apparatus using a transfer molding method.

FIG. 3 is a simplified explanatory diagram showing a molding apparatus using an injection molding method.

FIG. 4 is a vertical sectional view of an infrared sensor module.

FIG. 5 is a plan view of an infrared sensor module

FIG. 6 is a vertical sectional view of an infrared sensor module according to another embodiment.

FIG. 7 is a plan view of an infrared sensor module according to another embodiment.

FIG. 8 is a vertical sectional view of an infrared sensor module according to another embodiment.

FIG. 9 is a plan view of an infrared sensor module according to another embodiment.

FIG. 10 is a vertical sectional view of an optical lens.

FIG. 11 is a vertical sectional view of an optical lens of another embodiment.

FIG. 12 is a vertical sectional view of an infrared sensor module according to another embodiment.

FIG. 13 is a side view showing an assembly structure of an optical lens and a casing.

[Explanation of symbols]

 1 Mold 2 Holding Frame 3 Air Cylinder 3a First Air Supply Port 3b Second Air Supply Port 4 Plunger 4a Load Cell 5 Compressed Air Supply System 6 Heating Furnace 7 First Pressure Reducing Valve 8 Second Pressure Reducing Valve 9,11 Pressure Gauge 10, 12,13 Solenoid valve 14 Gas supply pipe 15 Temperature monitor 16 Mold 17 Housing 18 Fixed plate 19 Clamping cylinder 20 Clamping ram 21 Movable plate 22 Raw material reservoir 23 Injection cylinder 24 Injection and pressure holding cylinder 24a 1st air inlet 24b Second air supply port 25 Piston 26 Horizontal heating furnace 27 Heater 28 Gas supply port 29 Gas supply system 30 Metal package 31 Optical filter 32 Light receiving part 33 Casing 34 Printed board 34a Hole 35 Metal layer 36 Metal layer 36a Part 37 Plating part 38 Coating layer 39 Coating layer 40 Guide groove 40a Recess 41 Engagement piece 41a Envelope engagement M Infrared sensor module N Infrared element K Casing R Optical lens r Convex lens Z Incident angle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location G01J 1/04 G01J 1/04 A G02B 1/00 G02B 1/00 1/10 13/14 13 / 14 1/10 Z // G01V 8/14 9406-2G G01V 9/04 C

Claims (11)

[Claims] 1. An optical lens capable of transmitting infrared rays is
e, Si or a Ge-Si alloy material, and the raw material is melt-molded by a molding method, and the molding method is performed by changing the injection pressure and the holding pressure of the melt into the mold. Controllable forming means, melting means for heating and melting a raw material made of Ge, Si or Ge-Si alloy material above its melting point, and after heating the forming die above the melting point of the raw material, the melt of the raw material is melted. Injecting means for injecting into the cavity of the mold at a predetermined pressure, cooling means for intensifying the injecting pressure after injection and cooling while maintaining a relatively high molding pressure, and in the cooling process thereof, near the freezing point. An infrared ray characterized by comprising first maintaining means for weakening the injection pressure to maintain a low holding pressure and second maintaining means for strengthening the pressure again when passing the freezing point to maintain a predetermined holding pressure. Manabu lens. 2. The infrared optical lens according to claim 1, wherein a metal layer formed by vapor-depositing a metal is provided on a part or the whole of the infrared incident side surface of the optical lens. 3. An extrusion molding method as the molding means,
The infrared optical lens according to claim 1, wherein a melt of a raw material is injected into a molding die by using an injection molding method or a transfer molding method. 4. The infrared optical lens according to claim 1, wherein the mold is a mold made of a high-density carbon material having a cavity inner surface optically polished. 5. The infrared optical lens according to claim 1, wherein the molding die is a molding die obtained by optically polishing the inner surface of a cavity of a molding material on which a metal is ceramic-coated. 6. An infrared element for detecting infrared rays is attached to a base having electronic parts, a casing for covering the infrared element is fixedly mounted on the base, and an opening formed in the casing is provided with the casing. An infrared sensor module provided with an optical lens capable of transmitting infrared rays to an infrared element, wherein the optical lens is made of a raw material made of Ge, Si or a Ge-Si alloy material, and
The raw material is formed by melt-molding the raw material by a molding method, and the molding method is a raw material made of Ge, Si or Ge-Si alloy material, and molding means capable of controlling the injection pressure and the holding pressure of the melt into the molding die. Melting means for heating and melting the melting point of the raw material above the melting point of the raw material, and pouring means for injecting the melt of the raw material at a predetermined pressure into the cavity of the raw material after the casting, Cooling means for increasing the injection pressure to cool the molding material while maintaining a relatively high molding pressure; first maintaining means for weakening the injection pressure near the freezing point to maintain a low holding pressure in the cooling process; When the optical lens is passed, the pressure is reintensified to maintain a predetermined holding pressure, and the optical lens is configured so that its infrared ray incident surface is a curved convex surface that draws an arc with respect to the infrared element. Configured, and an infrared sensor module having a plurality of convex lens inner surface are configured to multi-lens, which are integrally formed. 7. The casing and the optical lens,
The infrared sensor module according to claim 6, which is made of a raw material made of Ge, Si or a Ge-Si alloy material, and the casing and the optical lens are integrally melt-molded by the molding method. 8. An engaged portion is formed on the casing, and an engaging portion for engaging with the engaged portion of the casing to fix the optical lens to the casing is formed on the optical lens. The infrared sensor module according to claim 6, wherein 9. An extrusion molding method as the molding means,
The infrared sensor module according to claim 6, wherein a melt of a raw material is injected into a molding die by using an injection molding method or a transfer molding method. 10. The infrared sensor module according to claim 6, wherein the molding die is a molding die in which a cavity material inner surface of a mold material made of a high-density carbon material is optically polished. 11. The infrared sensor module according to claim 6, wherein the molding die is a molding die obtained by optically polishing the inner surface of a cavity of a die material coated with ceramic on metal.